1. Field of Invention
This invention relates to composite fabrics, and particularly to soft shell composites.
2. Description of Related Art
In the development of fabrics intended for use in the manufacture of outerwear, certain properties relating primarily to wearer comfort have become especially desirable. Among these are warmth, soft handle, elasticity, and breathability. These properties, in turn, must be balanced with the largely opposing properties of cost, durability, weatherproofness and surface appearance, all of which are critical to end user acceptance.
An important class of performance fabrics, commonly referred to as “soft shell” or alternatively “softshell”, has emerged over the past couple of decades and represents the state-of-the-art among materials that attempt to balance these properties. These fabrics are typically multilayer laminates comprising an inner (next to skin) thermal knit fabric layer, an outer stretch woven fabric layer and optionally a functional barrier layer sandwiched between (see FIG. 5). The layers are typically bound together by a suitable adhesive system. These soft shell fabrics are well-recognized as having a familiar textile surface appearance and feel, while offering weather and abrasion resistance, and excellent wearer comfort. The latter being due to enhanced stretch and breathability characteristics relative to coated or laminated conventionally woven fabric counterparts, sometimes referred to as “hard shell” fabrics.
Within the soft shell fabric class itself one can find composites ranging in stretch from simply having noticeable “give”, to those having pretty significant stretch and recovery in either one or all planar dimensions. The same goes for breathability and water resistance. Some soft shells offer waterproofness with a moderate degree of moisture vapor transmission (breathability), while others are engineered to provide a significant, yet controlled, degree of air permeability, and are thus capable of even higher rates of moisture vapor transmission. The latter, more often than not, are then restricted to being categorized as “water resistant” since they have sacrificed the property of hydrostatic resistance in favor of permeability. These materials however can still be very effective in keeping the wearer dry owing to the fact that their outer surface fabrics are treated with rather powerful laundry durable, water and stain repellent finishes. In summary, quality soft shell fabrics provide the wearer with a good level of weather protection, and very high comfort.
Soft shell fabrics are relatively expensive however. The addition of “give” or more importantly, significant omnidirectional stretch, require that these laminates employ fabrics that themselves stretch. Conventional knit fabrics, napped or otherwise meet this requirement in many cases, and in fact are commonly used as the inner fabric component. However, wovens are strongly preferred as outer (face) fabric components due to their widely accepted look and superior resistance to snagging and pilling. But since conventional woven fabrics inherently lack much stretch, special manufacturing techniques must be employed to purposely impart this property. For this reason stretch woven fabrics demand a noticeable premium in the marketplace. It is no wonder then that after considering the relatively high cost of at least one of the component fabrics, and also the fact that these fabrics need to be adeptly laminated using systems that maintain breathability, the finished composite fabric and resulting constructed garment can be quite expensive.
Accordingly, it is desired to provide a method and apparatus for the economical production of air permeable soft shell fabrics that mimic conventional stretch woven faced fabric laminates. It is further desired to provide a method and apparatus for imparting controllable porosity to a coated fabric while maintaining the stretch, durability and handle of traditional transfer-coated fabrics. It is still further desired to provide a method and apparatus to increase coated fabric durability while maintaining adequate softness of hand for fabrics of varying porosities.